OK, I guess I'll be the one to ask this.
What barrel length, or rather velocity are these thigns calibrated for? This is especially important with the 45-70 as I have seen it in pistols, 16"barrel rifles all the way out to 34" barrel rifles. The diffrence in a 16" scout lever action and a 34" long range barreled gun is enough to make a diffrence in impact at 200yds by a decent amount.
They may be wonderful, I just have trouble seeing this though with all the variables in ballistics.
carp, be sure to let us know I for one will be waiting to see how it works for you (and hoping it works great for you)
George